The present invention relates to a display device, and more particularly to a display device which is referred to as “Field Emission Display” (hereinafter abbreviated as “FED”).
A structure of FED is disclosed, for example, in FIG. 21 of JP-A-2001-101965 (Document 1). This patent document discloses that a back substrate which has electron emission elements comprised of cold cathode elements arranged in matrix on an insulating substrate for use as an electron source is placed in opposition to a display substrate which is provided with luminescent materials of three primary colors R, G, B disposed on an optically transparent substrate made of glass or the like for emitting light through collisions of electrons from the electron source. Document 1 also discloses that a supporting frame hermetically seals the two substrates with frit glass between the peripheral edges thereof to maintain the interior under vacuum in a range of approximately 10−5 to 10−7 torr. A conductive metal reflective film (metal back) is also provided over the luminescent materials for use as an accelerating electrode which is supplied with a high voltage for accelerating electrons from the electron emission elements (hereinafter called the “accelerating voltage”).
Structures for supplying the accelerating voltage to the metal back are disclosed, for example, in JP-A-5-114372 (Document 2), JP-A-4-94043 (Document 3), JP-A-10-326581 (Document 4), and the like. The structure disclosed in Document 2 comprises a high voltage terminal which extends through a back substrate from the back of a vacuum chamber and has a leading end connected to a metal back, as shown in FIGS. 1 to 3 of Document 2. The structure disclosed in Document 3 comprises a display substrate which forms part of a vacuum chamber formed with a throughhole extending therethrough, and a high voltage terminal inserted into the throughhole and brought into contact with a conductor connected to a metal back, as shown in FIGS. 1 and 2 of Document 3. The structure disclosed in Document 4 comprises a cylindrical recess formed in a display substrate or a back substrate of a vacuum chamber, a conductor drawn out from a metal back to the recess, and a high voltage terminal connected to the conductor in the recess.